If $x \boxdot y = 2x-4y$ and $x \triangleright y = xy+2x-y$, find $(2 \boxdot 2) \triangleright -5$.
First, find $2 \boxdot 2$ $ 2 \boxdot 2 = (2)(2)-(4)(2)$ $ \hphantom{2 \boxdot 2} = -4$ Now, find $-4 \triangleright -5$ $ -4 \triangleright -5 = (-4)(-5)+(2)(-4)-(-5)$ $ \hphantom{-4 \triangleright -5} = 17$.